20MPH LIMITS/ZONES IN CARDIFF – AN INVESTIGATION
1.0 INTRODUCTION
1.1
This paper has been prepared following a reply from Cllr Ralph Cook
(Cabinet Member for Planning, Highways, Traffic and Transportation) to
a question from Cllr Dianne Rees at Full Council in June 2012 which she
asked, “Will you consider community wide 20mph limits like English
authorities which have a 20mph residential speed limit policy”.
1.2
In reply, Cllr Cook said he would, “ask officers to carry out an initial
investigation of the practical, legal and financial implications of
introducing 20mph zones in Cardiff. I will provide a briefing to Members
once the work has been completed.”
1.3
Leading Cardiff – Building Communities agreed by Cabinet at its
meeting in July set out the Administration’s vision and a number of key
priorities for the remainder of the current municipal year. It included a
commitment to Improve safety outside schools, to support the
development of school travel plans, to encourage walking and cycling to
school and create School Safety Zones, by ensuring enforceable
parking restrictions are in place at each school and that they are
robustly enforced. The document also included a commitment to support
District Shopping centres by improving walking, cycling and public
transport accessibility and put in place Parking Plans for each. Early on
in the assessment of the feasibility of these commitments, it became
clear that including measures to reduce vehicle speeds at key localities
on the city’s road network (particularly near schools and in shopping
areas), would need to be considered.
1.4
Speaking during Road Safety Week, the Welsh Government Minister
with responsibility for Transport, Carl Sargeant, called for more 20mph
zones in Wales. The Minister highlighted the Welsh Government’s
commitment to reducing the number of people that are killed or seriously
injured on our roads – drawing attention to the significant impact that
20mph zones can have on making our roads safer.
1.5
In 2012/13 the Welsh Government provided local authorities with a total
of £11.5m, which includes the improvement of accessibility, safety and
encourage walking and cycling within communities. In addition to other
traffic calming measures this funding can also be used to implement
20mph speed limits and zones. Research by the Welsh Government
suggests that 20mph zones can reduce road casualties by
approximately 40%.
Page 1 of 11
1.6
This research is supported by areas such as Sandfields district in Port
Talbot. Sandfields introduced a long term strategy of improving safety
on its roads that culminated in a blanket 20mph zone across the entire
estate. This led to a 48% reduction in personal injuries over a three
year period.
1.7
As the Welsh Government does not have the powers to change national
speed limits, the Minster announced that he will be writing to Welsh
Local Authorities shortly to encourage them to introduce more 20mph
zones.
1.8
At Full Council on 22nd November Cllr Ralph Cook, in reply to a further
question from Cllr Dianne Rees said: “I have considered the outcomes
of this [investigation] and…. I will be circulating next week the initial
briefing on this exercise that I have received for the benefit of all
Members”.
2.0 BACKGROUND
2.1
Reducing vehicular speeds in urban and residential areas to 20mph or
less is a key strategy for reducing road casualties, increasing modal shift
to walking and cycling as well as reducing noise and emissions.
Similarly the speed of traffic is often quoted as one of the main safety
factors which people see as a barrier to travelling around their
communities on foot or by bicycle or to letting children travel
independently. There are a number of reasons why speeds should be
reduced to 20mph:

To make walking and cycling safer and more attractive.

To help to reduce the number and seriousness of injuries
suffered by road casualties. There is robust evidence that lower
speed limits reduce the number and severity of collisions, with
a 2-7% reduction in collisions for every 1mph reduction in
average vehicle speeds. The fatality rate for pedestrians hit by
a car reduces from 31% at 40mph to 7% at 30 mph. At 20mph
the fatality rate is considerably lower still at around 2%.

Lower speed limits will encourage more outdoor active play
amongst children, leading to healthier communities.

To increase social inclusion and access for those without motor
vehicles.

To make local facilities more accessible e.g. by making
crossing roads easier. This is important for health and
wellbeing within local communities.
Page 2 of 11
2.2
Speeds can either be reduced through designating 20mph zones or
setting 20mph limits on roads:

A 20mph zone is indicated by 20mph zone entry and exit signs.
The regulations require traffic calming measures to be
implemented throughout the zone to ensure that the 20mph
speed limit is ‘self-enforcing’. No point in the "zone" can be
further than 50m from a traffic calming feature, unless the road
is a cul-de-sac of less than 80m in length.

A 20mph limit is indicated by speed limit signs and repeater
signs at regular intervals. 20 mph limits usually do not have any
traffic calming features. In June 2011, the Department for
Transport announced new signage rules allowing repeater
signs and carriageway 20mph signs to be accepted as Traffic
Calming Features, hence increasing flexibility and reducing
costs for local authorities implementing 20mph limits.
3.0 GUIDANCE
3.1
Circular No 24/2009 sets out the Welsh Government’s Guidance on
Setting Local Speed Limits in Wales, October 2009. This states that
Highway authorities may implement 20mph speed limits and zones
where appropriate, particularly in residential areas, and that this is
encouraged and supported by the Welsh Government. ‘20mph zones
have a proven casualty reduction benefit and are usually used in town
centres, residential areas and in the vicinity of schools. Their purpose is
to create conditions in which drivers naturally drive at around 20mph.’
3.2
The guidance also states that 20mph speed limits and zones should
ideally be self enforcing. ‘Highway authorities should take account of the
level of police enforcement required before installing either of these
measures and must always formally consult the police when considering
their use.’ The Guidance also advices that 20mph speed limits should
only be used where mean vehicle speeds are 24mph or below or where
traffic calming measures are planned as part of the speed management
strategy.
4.0 CARDIFF - CURRENT POSITION
4.1
Cardiff Council has implemented a rolling programme of measures
designed to tackle speeding. These have included traffic calming,
junction modification and improved pedestrian facilities and crossings.
Cardiff Council has also implemented at least 23 School Safety Zones
(SSZs) and seven 20mph zones, and work is continuing to implement
more schemes in 2012/13 as part of this overall programme.
Page 3 of 11
4.2
The works have been funded through Cardiff Council’s own capital
funding and Welsh Government funding through Road Safety Grant,
Safe Routes to Schools and Safe Routes in Communities programmes.
4.3
Schemes have historically been prioritised for funding using a priority
ranking system which takes into account: vehicle flows and speeds;
pedestrian data; casualty records; its contribution to the Council’s
policies and the scheme’s value. This produces a score that allows all
the schemes to be ranked against each other on an annual basis as part
of the determination of the capital programme.
4.4
In 2011, the Council adopted a Strategic Cycle Network Plan for the city.
This plan defines a core network of cycling routes and a 5 year
programme of schemes to deliver the network. Included within the 5
year programme is a proposal for an area-wide 20mph zone for the
Cathays area. An initial study has been undertaken to assess the
feasibility of implementing this proposal, concluding that with
stakeholder engagement, public consultation and more detailed
investigatory works the zone could be implemented.
4.5
In addition to the study for the Cathays area, a study investigating the
feasibility of introducing 20mph speed limit across parts of the city
centre and parts of adjacent city centre areas is also in progress. This
would require limited physical traffic calming as only signage is required
throughout the majority of the sites assessed.
5.0 CASE STUDIES
5.1
A growing number of English cities and towns have committed to a 20
mph speed limit on all or most of their residential streets. This approach
sets a new “societal norm” for vehicle speeds where people live, work,
shop, play and go to school. In Portsmouth, which implemented 20mph
limits on 94% of its roads in 2008, over 40% of respondents stated that
“there has been a safer environment for walking and cycling; and as a
result, around a third of respondents felt that there had been an increase
in pedestrian and cyclist activities in local areas”. This has been followed
by wide area implementations in other towns and cities, including:






Oxford - implemented “Total 20” on all its residential roads (Sep
2009)
Islington - implemented “Total 20” on all its residential roads
(March 2010)
Newcastle - converting all its “advisory” speed limits on
residential roads to mandatory 20 mph limits
Bristol - implementing 20 mph speed limits on 2/3 of the city
Warrington - implemented 20mph limits on 190 roads and is
rolling this out across the whole town, following on from a 20
mph limit trial in 2009/10
Wirral - announced a 3 year program to set 20mph limits for all
residential roads
Page 4 of 11









Edinburgh - announced a large 20mph limited area in the
Southern part of the city
Lancashire - has pledged all residential roads in the county to
have a 20mph limit by 2013
Brighton & Hove - committed to 20mph for all residential streets
Sheffield - rolling out area-wide 20mph limits as part a city-wide
review of signage
Liverpool - committed to 20mph limits on 70% of its residential
streets
York - planning the roll-out of 20mph limits across the whole
town
Portsmouth – 20mph speed limit implemented in 2006 on 1,200
residential roads
Hull - 120 20mph zones implemented across 500 streets in
2003
London - 399 20 mph zones implemented by 2007/08
5.2
Experience in other cities has shown that early engagement with local
communities is important to secure public support. Most residents in
areas where 20mph limits have been implemented strongly support their
introduction. The absence of speed humps and other traffic calming
measures help to increase public acceptance. The impact on journey
time is very small, whilst the improvement for other road users can be
significant.
5.3
Research undertaken on the introduction of 20mph zones shows that
these are even more effective at reducing collisions and injuries.
Overall, average annual accident frequency may fall by around 60%,
and the number of accidents involving injury to children may be reduced
by up to two-thirds. Zones may also bring further benefits, such as an
overall reduction in traffic flow. (Department for Transport, Speed Limit
Circular, December 16th, 2009.
5.4
More information on these schemes is provided in Table 1. This shows
case study evidence of the success of 20 mph zones and limits in a
number of UK cities and outlines casualty and speed statistics together
with financing information.
6.0 SUMMARY
6.1
The introduction of 20mph speed limits or zones would increase social
cohesion as well as demonstrating a Council commitment to making
streets safer and improving quality of life.
Page 5 of 11
6.2
The Council should continue to prioritise the implementation of school
safety zones through GCF Traffic management budget. 20 mph zones
are very effective in reducing casualties and represent good value for
money where it can be shown that current casualties are high. The cost
of the introduction of zones is approximately £60k per km.
6.3
Consideration should also be given to implementation of 20mph limits in
residential areas, shopping districts and near to parks where the speeds
are 24pmh or lower. Whilst 20 mph limits may be less effective than 20
mph zones in reducing speed, their cost is significantly lower, and their
lack of engineering may enable them to be rolled out faster and far wider
than 20 mph zones. The cost of the introduction of speed limits is
approximately £1k per km. The impact of the introduction of 20mph
limits could be tested through a pilot in the Cathays/Roath or Riverside
Safe Routes in Communities area, subject to funding.
Page 6 of 11
Table 1 - Case studies – include information from all listed schemes
City
Portsmouth
Hull
London
Background
20mph speed limit
implemented in 2006
across all 1,200
residential roads on
410km of its 438km
road network (94%
coverage).
120 20mph zones
implemented across
500 streets by 2003.
399 20 mph zones
implemented by
2007/08.
Practical
22% drop in collisions compared to the
average of the previous 3 years. On roads
where previously the average speed was
24-29 mph, speed was reduced by 6.5
mph.
Financial
£475,000. Equated to
just £333 per street or
£1,158 per km
Legal
The police use
“light touch”
enforcement which
complements the
other efforts of the
Council.
Casualty statistics between 1994 and 2001
show a drop of 14% in Hull
In the 20mph zones, there was a decrease
in total accidents by 56% and in fatal and
serious injuries by 90%.
Child casualties dropped by 54% and child
pedestrian casualties fell by 74%.
20 mph zones in London have a 42%
reduction in all casualties compared with
outside areas, with no evidence of collision
migration to other areas.
unknown
Road Traffic
Regulation Act
(Amendment) Order
1999
The cost
effectiveness analysis
suggested that the
benefits (in terms of
casualties prevented)
of 20 mph zones
implemented in high
casualty areas are
greater than the costs
of implementation,
Road Traffic
Regulation Act
(Amendment) Order
1999
Page 7 of 11
City
Background
Practical
Islington
20mph speed limit
on all side roads,
total of around 150
miles of street under
the limit.
20mph limits on over
500 roads using a
‘signs only 20mph’
approach
The number of people killed or seriously
injured on Islington's roads fell from 227 in
2001 to 77 in 2009, thought to be partly as
a result of lower speeds.
Bristol
65% of roads saw a reduction in mean
speeds.
18 roads no longer saw average speeds
above 24mph.
Increase in counts for walking range from
10% increase to 36% increase according to
whether looking at South pilot or East,
weekends or weekdays, and correcting (or
not) for rainy days.
Increase in counts for cycling range from
4% increase to 37% increase, according to
the same variables.
Page 8 of 11
Financial
whereas those in low
casualty areas are
not. The results show
that 20 mph zones
become cost effective
when a road has over
0.7 casualties per km.
Average cost per km
£59,334.16 in 2005.
No data available
Legal
No data available
Road Traffic
Regulation Act
(Amendment) Order
1999
Road Traffic
Regulation Act
(Amendment) Order
1999
City
Background
Oxford
Implemented “Total
20” on all its
residential roads
Converting all its
“advisory” speed
limits on residential
roads to mandatory
20 mph limits
Implemented 20
mph limits on 190
roads and is rolling
this out across the
whole town.
Newcastle
Warrington
This was
predeceased by a
trial in 2009/10
which imposed limits
Practical
Financial
Support for 20mph limits amongst pilot area
residents is around 82%.
Around 70% support a citywide expansion
of 20mph limits in residential areas.
89% of residents supported 20 mph on all
residential streets.
56% of residents supported 20mph on
‘main’ roads
No data available
No data available
Legal
No data available
No data available
No data available
The trial reported a 1.45mph reduction in
average speed across all 20 mph sites.
No data available
No data available
There was no notable change in cycle
usage indicated within the Orford area.
However, Great Sankey demonstrated a
20% increase in cycle numbers between
June 08 and July 2010, which may have
been a result of greater confidence in road
use due to lower passing vehicle speeds.
Page 9 of 11
No data available
City
Wirral
Edinburgh
Background
on 140 roads within
3 areas.
Announced a 3 year
program to set
20mph limits for all
residential roads
Announced a large
20mph limited area
Practical
Financial
Legal
There has been an overall reduction of 13.7
collisions over and above that which might
have been expected, which was mainly
achieved in the Orford trial area where
there was a reduction of 11.2 injury
collisions and 6 casualties.
A questionnaire was devised to investigate
public perception of 20 mph speed limits.
The survey indicated that the percentage of
respondents that were cyclists had
increased steadily throughout the pilot
study, rising from 28% to 40%. 75% of
respondents felt that police enforcement is
a necessity to gain compliance from
motorists. 77% of respondents would like to
see the 20mph speed limit become a
permanent order in their area.
No data available
No data available
No data available
No data available
No data available
No data available
Page 10 of 11
City
Lancashire
Brighton &
Hove
Sheffield
Liverpool
York
Background
in the Southern part
of the city
Has pledged all
residential roads in
the county to have a
20mph limit by 2013
Committed to 20mph
for all residential
streets
Rolling out areawide 20mph limits as
part a city-wide
review of signage
Committed to 20mph
limits on 70% of its
residential streets
Planning the roll-out
of 20mph limits
across the whole
town
Practical
Financial
Legal
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
No data available
Page 11 of 11